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A test of resuspension factor models against Chernobyl data

Description: After the accident at Unit 4 of the Chernobyl nuclear power plant (NPP), stationary air samplers were operated at Chernobyl and Baryshevka, cities which are 16 km and 150 km, respectively, from the NPP. Other air samplers were operated simultaneously, but intermittently, at locations within the 30 km zone at distances of 4-25 km from the NPP. These data were used to check the validity of time dependent models of the resuspension factor K (m{sup -1}). Seven different models were examined, three of which are discussed in the paper. Data from the stationary air samplers were averaged over one day or one month; dam from the intermittent air samplers were averaged over three days in 1986 and over four hours in 1991. The concentrations of eight radionuclides were measured at ten points during the same time period (14-17 September 1986). The calculated resuspension factors range from 6 x 10{sup -9} m{sup -1} to 3 x 10{sup -6} m{sup -1}. Data for the spatial means of K are given for certain time periods in 1986 and 1991; also presented are the calculated values according to the models. The experimental data and the calculated values differ by up to more than one order of magnitude. Also analysed was the temporal change in experimental values of K and these values were compared with model predictions. The annual means of the resuspension factor as determined experimentally and as calculated with the models are presented. The model derived from empirical data measured in Neuherberg after the Chernobyl accident agrees best with the data. The Garland model systematically gives results lower than the experimental values, and the calculated values of K from the Linsley model are consistently conservative. Also considered were the uncertainty of K due to fluctuations in air concentrations and possible biological effects of ...
Date: April 1, 1995
Creator: Garger, E.K.; Anspaugh, L.R.; Shinn, J.H. & Hoffman, F.O.
Partner: UNT Libraries Government Documents Department

Bryansk feasibility study: Initial start-up phase. Final progress report

Description: US investigators have been collaborating with investigators in Russia and other parts of the former Soviet Union to give technical, scientific, and methodological support for dose reconstruction work in Kaluga and Bryansk Oblasts which were contaminated by the Chernobyl accident. A team traveled to Bryansk to perform in situ measurements at residences, to collect samples, and to administer questionnaires related to individual dose estimation. Samples were also obtained from soil, food, and of bricks. This report presents the accomplishments that have been made in the following areas: collaborations and communications; epidemiology; and radiation dose estimation.
Date: May 1, 1996
Partner: UNT Libraries Government Documents Department

Pioneer Robot Testing Program and Status

Description: The U.S. Department of Energy (USDOE) and Ukraine established a joint program in 1997 to address the need for remotely operated systems for unstructured environments in Ukraine such as the highly hazardous conditions inside the failed Chernobyl Nuclear Power Plant (ChNPP) Unit 4, or Shelter Object. The environment inside Shelter Object is extremely hazardous due to ionizing radiation fields, high airborne contamination, and major industrial safety issues. Although Ukrainian workers have explored and mapped much of the internals of Unit 4 in the time since the accident during the morning hours of April 26, 1986, there remain areas where humans have not entered to this date. Based on the agreement between USDOE and Ukraine, the USDOE, in cooperation with the U.S. National Aeronautics and Space Administration (NASA), developed the Pioneer Robot and has provided it to the ChNPP within the framework of international technical assistance. Pioneer is capable of mobile platform movement and manipulation under teleoperated control, 3-dimensional mapping, and environmental data collection. The Pioneer is radiation hardened for conditions like those of Shelter Object. Pioneer has been evaluated on site in Ukraine for use in both the Shelter Object environment and the more general conditions of ChNPP decommissioning. This paper summarizes the results of these testing activities and describes the status and near-term activities in support of the Pioneer Robot integration into Ukraine.
Date: February 2, 2001
Creator: Herndon, J.N.
Partner: UNT Libraries Government Documents Department

Nuclear analysis of the chornobyl fuel containing masses with heterogeneous fuel distribution.

Description: Although significant data has been obtained on the condition and composition of the fuel containing masses (FCM) located in the concrete chambers under the Chernobyl Unit 4 reactor cavity, there is still uncertainty regarding the possible recriticality of this material. The high radiation levels make access extremely difficult, and most of the samples are from the FCM surface regions. There is little information on the interior regions of the FCM, and one cannot assume with confidence that the surface measurements are representative of the interior regions. Therefore, reasonable assumptions on the key parameters such as fuel concentration, the concentrations of impurities and neutron poisons (especially boron), the void fraction of the FCM due to its known porosity, and the degrees of fuel heterogeneity, are necessary to evaluate the possibility of recriticality. The void fraction is important since it introduces the possibility of water moderator being distributed throughout the FCM. Calculations indicate that the addition of 10 to 30 volume percent (v/o) water to the FCM has a significant impact on the calculated reactivity of the FCM. Therefore, water addition must be considered carefully. The other possible moderators are graphite and silicone dioxide. As discussed later in this paper, silicone dioxide moderation does not represent a criticality threat. For graphite, both heterogeneous fuel arrangements and very large volume fractions of graphite are necessary for a graphite moderated system to go critical. Based on the observations and measurements of the FCM compositions, these conditions do not appear creditable for the Chernobyl FCM. Therefore, the focus of the analysis reported in this paper will be on reasonable heterogeneous fuel arrangements and water moderation. The analysis will evaluate a range of fuel and diluent compositions.
Date: October 14, 1998
Creator: Turski, R. B.
Partner: UNT Libraries Government Documents Department

Estimated long term health effects of the Chernobyl accident

Description: Apart from the dramatic increase in thyroid cancer in those exposed as children, there is no evidence to date of a major public health impact as a result of radiation exposure due to the Chernobyl accident in the three most affected countries (Belarus, Russia, and Ukraine). Although some increases in the frequency of cancer in exposed populations have been reported ,these results are difficult to interpret, mainly because of differences in the intensity and method of follow-up between exposed populations and the general population with which they are compared. If the experience of the survivors of the atomic bombing of Japan and of other exposed populations is applicable, the major radiological impact of the accident will be cases of cancer. The total lifetime numbers of excess cancers will be greatest among the `liquidators` (emergency and recovery workers) and among the residents of `contaminated` territories, of the order of 2000 to 2500 among each group (the size of the exposed populations is 200,000 liquidators and 3,700,000 residents of `contaminated` areas). These increases would be difficult to detect epidemiologically against an expected background number of 41500 and 433000 cases of cancer respectively among the two groups. The exposures for populations due to the Chernobyl accident are different in type and pattern from those of the survivors of the atomic bombing of Japan. Thus predictions derived from studies of these populations are uncertain. The extent of the incidence of thyroid cancer was not envisaged. Since only ten years have lapsed since the accident, continued monitoring of the health of the population is essential to assess the public health impact.
Date: July 1, 1996
Creator: Cardis, E.
Partner: UNT Libraries Government Documents Department

United States: Ukraine Technical Exchange II trip report

Description: May 15--21, 1994, the first technical conference was held at Hanford between Ukraine-Chornobyl, Westinghouse Hanford, and SAIC, to exchange technical information and experience gained in cleanup and stabilization of radioactive contamination at Hanford and Chornobyl. Protocol was signed for a second exchange and technology demonstration program in Kiev and near Chornobyl power plants. Technical Exchange No. 2 was held from August 28--September 9, 1994, with 3 focus areas: field demonstration of DOE-Hanford technologies and application to cleanup of contaminated lands resulting from 1986 Chornobyl accident; application of other US DOE-technologies; and observation/evaluation of Ukraine-developed technologies for potential application in USA. Three radiological mapping systems were demonstrated near Chornobyl: man-carried Ultrasonic Ranging and Data System, a mobile radiological data system, and NOMAD field gamma spectroscopy system. The Ukraine-Chornobyl team hosted technical presentations, discussions and field trips for 4.5 days, providing insight on the Chornobyl problem and allowing the US team to present overviews on DOE technologies that may be applicable to the Chornobyl situation. It is concluded that Ukrainian scientists have tremendous talent and expended considerable energy in attempting to tackle such a problem, but economic and cultural conditions with Ukraine have prevented them from acquiring the resources to implement basic aspects of characterization and remediation activities. Most of their publications are in Russian only. Their translation, plus resources to carry out proposals for bench scale and field demonstration projects, could benefit the DOE complex and other nuclear programs. The considerable cultural and economic change occurring in Ukraine, is providing opportunities for private industries to assist in the changes and for DOE, others to apply cleanup technologies, and it is essential that close institutional relations be established.
Date: February 1, 1995
Creator: Moak, D.J. & Wendling, M.A.
Partner: UNT Libraries Government Documents Department

Consequences of the Chernobyl accident for the natural and human environments

Description: In the ten years since the Chernobyl accident, an enormous amount of work has been done to assess the consequences to the natural and human environment. Although it is difficult to summarize such a large and varied field, some general conclusions can be drawn. This background paper includes the main findings concerning the direct impacts of radiation on the flora and fauna; the general advances of knowledge in the cycling of radionuclides in natural, seminatural and agricultural environments; some evaluation of countermeasures that were used; and a summary of the human radiation doses resulting from the environmental contamination. although open questions still remain, it can be concluded that: (1) at high radiation levels, the natural environment has shown short term impacts but any significant long term impacts remain to be seen; (2) effective countermeasures can be taken to reduce the transfer of contamination from the environment to humans but these are highly site specific and must be evaluated in terms of practicality as well as population does reduction; (3) the majority of the doses have already been received by the human population. If agricultural countermeasures are appropriately taken, the main source of future doses will be the gathering of food and recreational activities in natural and seminatural ecosystems.
Date: July 1, 1996
Creator: Dreicer, M.; Aarkog, A.; Alexakhin, R.; Anspaugh, L.; Arkhipov, N.P. & Johansson, K.-J.
Partner: UNT Libraries Government Documents Department

Estimated long-term health effects

Description: Apart from the dramatic increase in thyroid cancer in those exposed as children, there is no evidence to date of a major public health impact of the radiation exposure from the Chernobyl accident in the three most affected countries. Although some increases in the frequency of cancer in exposed populations have been reported, these results are difficult to interpret, mainly because of differences in the intensity and method of follow-up between exposed populations and the general population to which they are compared. If the experience of atomic bomb survivors and of other exposed populations is applicable, the major radiological impact of the accident will be cancer and the total lifetime numbers of excess cancers will be greatest among the liquidators and among the residents of contaminated territories, of the order of 2,000 to 2,500. These increases would be difficult to detect epidemiologically against an expected background number of 41,500 and 433,000 respectively (size of the exposed populations: 200,000 and 3,700,000, respectively). It is noted, however, that the exposures received by populations exposed as a result of Chernobyl are different (in type and pattern) from those of atomic bomb survivors. Predictions derived from these populations are therefore uncertain. Indeed, the extent of the increase in thyroid cancer incidence in persons exposed as children was not foreseen. In addition, only ten years have passed since the accident. It is essential therefore that monitoring of the health of the population be continued in order to assess the public health impact of the accident, even if, apart from leukemia among liquidators, little detectable increase of cancers due to radiation from the Chernobyl accident is expected.
Date: April 1, 1996
Creator: Cardis, F.; Okeanov, A.E.; Likthariev, I.; Prisyazhniuk; Anspaugh, L.R.; Mabuchi, K. et al.
Partner: UNT Libraries Government Documents Department

Application of the RESRAD computer code to VAMP scenario S

Description: The RESRAD computer code developed at Argonne National Laboratory was among 11 models from 11 countries participating in the international Scenario S validation of radiological assessment models with Chernobyl fallout data from southern Finland. The validation test was conducted by the Multiple Pathways Assessment Working Group of the Validation of Environmental Model Predictions (VAMP) program coordinated by the International Atomic Energy Agency. RESRAD was enhanced to provide an output of contaminant concentrations in environmental media and in food products to compare with measured data from southern Finland. Probability distributions for inputs that were judged to be most uncertain were obtained from the literature and from information provided in the scenario description prepared by the Finnish Centre for Radiation and Nuclear Safety. The deterministic version of RESRAD was run repeatedly to generate probability distributions for the required predictions. These predictions were used later to verify the probabilistic RESRAD code. The RESRAD predictions of radionuclide concentrations are compared with measured concentrations in selected food products. The radiological doses predicted by RESRAD are also compared with those estimated by the Finnish Centre for Radiation and Nuclear Safety.
Date: March 1, 1997
Creator: Gnanapragasam, E. K. & Yu, C.
Partner: UNT Libraries Government Documents Department

The characterization and risk assessment of the `Red Forest` radioactive waste burial site at Chernobyl Nuclear Power Plant

Description: The `Red Forest` radioactive waste burials created during emergency clean-up activities at Chernobyl Nuclear Power Plant represent a serious source of radioactive contamination of the local ground water system with 9OSr concentration in ground water exceeding the drinking water standard by 3-4 orders of magnitude. In this paper we present results of our hydrogeological and radiological `Red Forest` site characterization studies, which allow us to estimate 9OSr subsurface migration parameters. We use then these parameters to assess long terrain radionuclide transport to groundwater and surface water, and to analyze associated health risks. Our analyses indicate that 9OSr transport via ground water pathway from `Red Forest` burials to the adjacent Pripyat River is relatively insignificant due to slow release of 9OSr from the waste burials (less than 1% of inventory per year) and due to long enough ground water residence time in the subsurface, which allows substantial decay of the radioactive contaminant. Tins result and our previous analyses indicate, that though conditions of radioactive waste storage in burials do not satisfy Ukrainian regulation on radiation protection, health risks caused by radionuclide migration to ground water from `Red Forest` burials do not justify application of expensive countermeasures.
Date: June 1, 1996
Creator: Bungai, D.A.; Skalskij, A.S.; Dzhepo, S.P. & Waters, R.D.
Partner: UNT Libraries Government Documents Department

Summary of gamma spectrometry on local air samples from 1985--1995

Description: This report summarizes the 1985--1995 results of low-level HPGe gamma spectrometry analysis of high-volume air samples collected at the Aiken Airport, which is about 25 miles north of SRS. The author began analyzing these samples with new calibrations using the newly developed GRABGAM code in 1985. The air sample collections were terminated in 1995, as the facilities at the Aiken Airport were no longer available. Air sample measurements prior to 1985 were conducted with a different analysis system (and by others prior to 1984), and the data were not readily available. The report serves to closeout this phase of local NTS air sample studies, while documenting the capabilities and accomplishments. Hopefully, the information will guide other applications for this technology, both locally and elsewhere.
Date: April 2, 1997
Creator: Winn, W.G.
Partner: UNT Libraries Government Documents Department

Needs assessment for remote systems technology at the Chornobyl Unit 4 shelter

Description: The accident at Chornobyl Unit 4 on April 26, 1986, resulted in a series of unprecedented scientific and technical challenges. The reactor building was damaged extensively. Following the accident, immediate action was needed to seal off the gaping crater created by the accident, which was a continuing source of airborne contamination. Under extreme conditions, a structure called the {open_quotes}Shelter{close_quotes} was built over the remains of the reactor building. The Shelter, which was quickly completed in November 1986, was meant to provide immediate but temporary containment. Now, 11 years later, there are significant concerns about its structural integrity and projected life expectancy. The United States and other participating G-7 countries are supporting nuclear safety upgrade efforts in Eastern Europe with a primary focus on placing the Chornobyl Nuclear Power Plant (ChNPP) Unit 4 Shelter in a stable and environmentally acceptable condition. Application of remote systems technologies will play an important part in achieving the goals of this program. The G-7 nations have agreed to support these efforts, including the identification and development of remote system technologies for fuel removal. However at this time they have taken a firm stance against funding actual fuel removal activities. The U.S. Department of Energy Office of Nuclear Energy, Science and Technology requested that a needs assessment be performed to evaluate the requirements for applying remote systems, including robotics, at the Shelter. This document is intended to be used to identify remote systems needs and requirements at the Shelter and to provide general information on the conditions in the Shelter that could impact the use of remote systems. This document is intended as a source of information to assist those who will be implementing the Shelter Implementation Plan tasks. The document provides background information and general guidance on the application of remote systems.
Date: December 1, 1997
Creator: Carteret, B.A.; Holliday, M.A. & Jones, E.D.
Partner: UNT Libraries Government Documents Department

Chernobyl lessons learned review of N Reactor

Description: A broad-base review of the N Reactor plant, design characteristics, administrative controls and responses unique to upset conditions has been completed. The review was keyed to Nuclear Regulatory Commission (NRC)-defined issues associated with the Chernobyl accident. Physical features of N Reactor that preclude an accident like Chernobyl include: lack of autocatalytic reactivity insertion (i.e., negative coolant void and power coefficents) and two separate, fast-acting scram systems. Administrative controls in place at N Reactor would effectively protect against the operator errors and safety violations that set up the Chernobyl accident. Several items were identified where further near-term action is appropriate to ensure effectiveness of existing safety features: Resolve a question concerning the exact point at which Emergency Core Cooling System (ECCS) activation by manual actions should be implemented or deferred if automatic ECCS trip fails. Ensure appropriate revision of the Emergency Response Guides and full communication of the correct procedure to all Operations, Safety and cognizant Technology staff. Train reactor operators in the currently recognized significance of the Graphite and Shield Cooling System (GSCS) in severe accident situations and cover this appropriately in the Emergency Response Guides. Complete reviews which establish an independent verification that pressure tube rupture will not propagate to other tubes. 15 refs., 3 tabs.
Date: October 1, 1987
Creator: Weber, E.T.; McNeece, J.P.; Omberg, R.P.; Stepnewski, D.D.; Lutz, R.J.; Henry, R.E. et al.
Partner: UNT Libraries Government Documents Department

Proceedings of the Chornobyl phytoremediation and biomass energy conversion workshop

Description: Many concepts, systems, technical approaches, technologies, ideas, agreements, and disagreements were vigorously discussed during the course of the 2-day workshop. The workshop was successful in generating intensive discussions on the merits of the proposed concept that includes removal of radionuclides by plants and trees (phytoremediation) to clean up soil in the Chornobyl Exclusion Zone (CEZ), use of the resultant biomass (plants and trees) to generate electrical power, and incorporation of ash in concrete casks to be used as storage containers in a licensed repository for low-level waste. Twelve years after the Chornobyl Nuclear Power Plant (ChNPP) Unit 4 accident, which occurred on April 26, 1986, the primary 4radioactive contamination of concern is from radioactive cesium ({sup 137}Cs) and strontium ({sup 90}Sr). The {sup 137}Cs and {sup 90}Sr were widely distributed throughout the CEZ. The attendees from Ukraine, Russia, Belarus, Denmark and the US provided information, discussed and debated the following issues considerably: distribution and characteristics of radionuclides in CEZ; efficacy of using trees and plants to extract radioactive cesium (Cs) and strontium (Sr) from contaminated soil; selection of energy conversion systems and technologies; necessary infrastructure for biomass harvesting, handling, transportation, and energy conversion; radioactive ash and emission management; occupational health and safety concerns for the personnel involved in this work; and economics. The attendees concluded that the overall concept has technical and possibly economic merits. However, many issues (technical, economic, risk) remain to be resolved before a viable commercial-scale implementation could take place.
Date: June 1, 1998
Creator: Hartley, J. & Tokarevsky, V.
Partner: UNT Libraries Government Documents Department

Macroscopic cross section generation and application for coupled spatial kinetics and thermal hydraulics analysis with SAS-DIF3DK

Description: This paper discusses the importance of modeling the transient behavior of multigroup cross sections in the context of coupled reactor physics and thermal-hydraulic computations with the SAS-DIF3DK computer code. The MACOEF macroscopic cross section methodology is presented. Results from benchmark verification calculations with a continuous-energy Monte Carlo are reported. Analysis of the Chernobyl accident is made using correlated WIMS-D4M generated group constants with special emphasis placed on the impact of modeling assumptions on the progression of the accident simulation.
Date: August 1, 1997
Creator: Turski, R.B.; Morris, E.E.; Taiwo, T.A. & Cahalan, J.E.
Partner: UNT Libraries Government Documents Department

Perspectives on reactor safety. Revision 1

Description: The US Nuclear Regulatory Commission (NRC) maintains a technical training center at Chattanooga, Tennessee to provide appropriate training to both new and experienced NRC employees. This document describes a one-week course in reactor safety concepts. The course consists of five modules: (1) the development of safety concepts; (2) severe accident perspectives; (3) accident progression in the reactor vessel; (4) containment characteristics and design bases; and (5) source terms and offsite consequences. The course text is accompanied by slides and videos during the actual presentation of the course.
Date: November 1, 1997
Creator: Haskin, F.E.; Camp, A.L. & Hodge, S.A.
Partner: UNT Libraries Government Documents Department

United States-assisted studies on dose reconstruction in the former Soviet Union

Description: Following the Chernobyl accident, the US and the USSR entered into an agreement to work on the safety of civilian nuclear reactors; one aspect of that work was to study the environmental transport and health effects of radionuclides released by the accident. After the break-up of the USSR separate agreements were established between the US and Ukraine, Belarus, and Russia to continue work on dose reconstruction and epidemiologic studies of health effects from exposure to external radiation and the incorporation of radionuclides. Studies in Belarus and Ukraine related to the Chernobyl accident now emphasize epidemiologic: studies of childhood-thyroid cancer and leukemia, and eye-lens-cataract formation in liquidators. Supporting studies on dose reconstruction emphasize a variety of ecological, physical, and biological techniques. Studies being conducted in Russia currently emphasize health effects in the workers and the population around the Mayak Industrial Association. As this production complex is an analogue of the US Hanford Works, advantage is being taken of the US experience in conducting a similar, recently completed dose-reconstruction study. In all cases the primary work on dose reconstruction is being performed by scientists from the former Soviet Union. US assistance is in the form of expert consultation and participation, exchange visits, provision of supplies and equipment, and other forms of local assistance.
Date: December 1, 1995
Creator: Anspaugh, L.R. & Bouville, A.
Partner: UNT Libraries Government Documents Department

Working Group 7.0 Environmental Transport and Health Effects, Chernobyl Studies Project. Progress report, October 1994 -- March 1995

Description: This document presents the details from the working group 7.0 Chernobyl Studies Project. This working group looked at the environmental transport and health effects from the fallout due to the meltdown of Chernobylsk-4 reactor. Topics include: hydrological transport; chromosome painting dosimetry; EPR, TL and OSL dosimetry; stochastic effects; thyroid studies; and leukemia studies.
Date: June 1, 1995
Creator: Anspaugh, L.R. & Hendrickson, S.M.
Partner: UNT Libraries Government Documents Department

Twenty years of improvements in LWR safety

Description: Substantial improvements have been made in the safety of light-water reactors in the US during the past two decades, making currently operating reactors safer than ever before. Safety improvements have resulted both from regulatory and operational changes and from new knowledge and technology. The US Nuclear Regulatory Commission, the US Department of Energy, and the American nuclear power industry have worked together and with the international community to enhance the safety of existing plants and to incorporate lessons learned from prior operation into designs for a new generation of advanced, inherently safer reactors.
Date: May 1, 1996
Creator: Franks, S. III; Mulkey, J.P.; Deitrich, L.W. & Moonka, A.
Partner: UNT Libraries Government Documents Department

Technical evaluation of proposed Ukrainian Central Radioactive Waste Processing Facility

Description: This technical report is a comprehensive evaluation of the proposal by the Ukrainian State Committee on Nuclear Power Utilization to create a central facility for radioactive waste (not spent fuel) processing. The central facility is intended to process liquid and solid radioactive wastes generated from all of the Ukrainian nuclear power plants and the waste generated as a result of Chernobyl 1, 2 and 3 decommissioning efforts. In addition, this report provides general information on the quantity and total activity of radioactive waste in the 30-km Zone and the Sarcophagus from the Chernobyl accident. Processing options are described that may ultimately be used in the long-term disposal of selected 30-km Zone and Sarcophagus wastes. A detailed report on the issues concerning the construction of a Ukrainian Central Radioactive Waste Processing Facility (CRWPF) from the Ukrainian Scientific Research and Design institute for Industrial Technology was obtained and incorporated into this report. This report outlines various processing options, their associated costs and construction schedules, which can be applied to solving the operating and decommissioning radioactive waste management problems in Ukraine. The costs and schedules are best estimates based upon the most current US industry practice and vendor information. This report focuses primarily on the handling and processing of what is defined in the US as low-level radioactive wastes.
Date: June 1, 1996
Creator: Gates, R.; Glukhov, A. & Markowski, F.
Partner: UNT Libraries Government Documents Department

Proposed radiation hardened mobile vehicle for Chernobyl dismantlement and nuclear accident response

Description: Researchers are developing a radiation hardened, Telerobotic Dismantling System (TDS) to remediate the Chernobyl facility. To withstand the severe radiation fields, the robotic system, will rely on electrical motors, actuators, and relays proven in the Chernobyl power station. Due to its dust suppression characteristics and ability to cut arbitrary materials the authors propose using a water knife as the principle tool to slice up the large fuel containing masses. The front end of the robot will use a minimum number of moving parts by locating most of the susceptible and bulky components outside the work area. Hardened and shielded video cameras will be designed for remote control and viewing of the robotic functions. Operators will supervise and control robot movements based on feedback from a suite of sensory systems that would include vision systems, radiation detection and measurement systems and force reflection systems. A gripper will be instrumented with a variety of sensors (e.g. force, torque, or tactile), allowing varying debris surface properties to be grasped. The gripper will allow the operator to manipulate and segregate debris items without entering the radiologically and physically dangerous dismantlement operations area. The robots will initially size reduce the FCM`s to reduce the primary sources of the airborne radionuclides. The robot will then remove the high level waste for packaging or decontamination, and storage nearby.
Date: January 1995
Creator: Rowland, M. S.; Holliday, M. A.; Karpachov, J. A. & Ivanov, A.
Partner: UNT Libraries Government Documents Department

Eliminating the possibility at Chernobyl 4 of recriticality with positive feedback

Description: We have recently published an article in which we discuss means by which plutonium and other fissile material stored underground could reach criticality with positive feedback and therefore explosive potential. The Chernobyl rubble involving hundreds of tons of material is similar in some respects to the systems analyzed in the paper, and the practices there to control criticality may well increase the probability of a second event at Chernobyl 4. This paper explores the Chernobyl situation and remedial actions are recommended.
Date: April 29, 1996
Creator: Bowman, C. D.
Partner: UNT Libraries Government Documents Department